What is PCOS? Signs, causes and what helps

Maybe your periods come whenever they like. Maybe you’ve noticed new hair on your chin, acne that won’t settle, or changes in your weight that are hard to explain. If a friend, a forum or a healthcare professional has mentioned PCOS, you probably have questions. This guide answers the big ones: what PCOS is, why it happens, how it’s diagnosed and what actually helps.

PCOS in a minute

Polycystic ovary syndrome, or PCOS, is a common hormonal condition. In PCOS, the body tends to make more androgens than usual. Androgens are hormones like testosterone. Everyone has them, but women usually have them in small amounts. Many people with PCOS also have insulin resistance, which affects how the body handles sugar.

Together, these changes can affect your periods, your skin and hair, your weight, your mood and your fertility. PCOS is also linked to your long-term health, which is why it’s worth understanding even if your symptoms are mild.

And it’s very common. The World Health Organization estimates that PCOS affects 10 to 13 percent of women of reproductive age, and that up to 70 percent of them haven’t been diagnosed. Researchers put the total at more than 170 million women worldwide, or about 1 in 8.

PCOS has a new name: PMOS

In May 2026, an international group of experts announced a new name for PCOS: polyendocrine metabolic ovarian syndrome, or PMOS. The change was published in The Lancet after 14 years of work with patients, health professionals and 56 patient and professional organizations.

Why change it? The old name pointed to cysts on the ovaries, but research shows that people with the condition don’t have more abnormal ovarian cysts. The old name also led some people to believe they needed surgery for cysts, and it hid the fact that the condition affects the whole body. The new name describes it better:

• Polyendocrine: many hormones are involved, including insulin.
• Metabolic: it affects how your body uses energy, with links to insulin resistance, type 2 diabetes and heart health.
• Ovarian: the ovaries are still part of the story.
• Syndrome: a group of signs that tend to appear together.

Common signs

PCOS looks different in different people. You might have one or two signs, or several, and they can change over time. Signs often start around the time of a first period, but many people only find out years later.

The most common signs are:

• Irregular periods: periods that come far apart, are hard to predict or stop altogether. Some people have heavy or long periods.
• Extra hair on the face, chest, back or belly.
• Thinning hair on the scalp.
• Acne or oily skin.
• Weight gain, or finding it hard to lose weight.
• Dark, thick patches of skin, often on the neck or in the armpits.
• Trouble getting pregnant.
• Feeling tired, low or anxious.

You don’t need to have all of these to have PCOS, and having one of them doesn’t mean you do. That’s why a proper check with a healthcare professional matters.

What causes PCOS?

No one knows the exact cause yet. What we do know is that a few things work together:

• Higher androgens. The ovaries make more androgens than usual, which can lead to extra hair, acne and irregular periods.
• Insulin resistance. Your body makes insulin but doesn’t respond to it well, so it makes more. High insulin levels can lead the ovaries to make even more androgens.
• Your genes. PCOS runs in families. Your risk is higher if a close relative has PCOS or type 2 diabetes, and the NHS notes that it’s more common in people of Asian background.

One more thing is worth saying clearly: PCOS isn’t caused by anything you did. It’s not your fault.

How PCOS is diagnosed

There’s no single test for PCOS. It’s usually diagnosed when you have at least two of these three features, and other conditions that can look similar have been ruled out:

1. Irregular or missing periods, a sign that you aren’t releasing an egg every month.
2. Signs of higher androgens, such as extra hair or acne, or high androgen levels in a blood test.
3. Polycystic ovaries on an ultrasound scan, or a high level of a hormone called AMH in a blood test.

You may also be asked about your symptoms and your family’s health, have your blood pressure checked, and have blood tests to rule out other causes, such as thyroid problems.

For teenagers, the rules are a little different. Cycles can be irregular for the first few years after a first period, so a diagnosis needs both irregular cycles and signs of higher androgens. Ultrasound also isn’t used to diagnose PCOS in the first eight years after a first period.

And despite the old name, you don’t need cysts on your ovaries to have PCOS.

Why it matters for your long-term health

PCOS isn’t only about periods. It can raise your risk of:

• type 2 diabetes: the CDC says more than half of women with PCOS develop type 2 diabetes by age 40
• high blood pressure and high cholesterol
• heart disease
• sleep apnea
• fatty liver disease
• diabetes during pregnancy
• endometrial cancer, a cancer of the lining of the uterus

It can also affect how you feel. People with PCOS are more likely to have anxiety, depression, eating disorders and a negative body image. That isn’t a weakness. It’s part of the condition, and it deserves care too.

The good news is that knowing these risks helps you stay ahead of them. The 2023 international PCOS guideline recommends:

• a blood sugar check when you’re diagnosed, then every one to three years
• a blood pressure check every year
• a cholesterol check when you’re diagnosed
• questions about your mood and anxiety, so you can get support early

What helps

There’s no cure for PCOS yet, but there’s a lot you can do. Most of it is about small, steady habits rather than big changes.

Eat in a way that works for you

There’s no single “PCOS diet”. The 2023 guideline found that no one way of eating works better than the others. A balanced pattern you enjoy and can keep up, with vegetables, fruit, whole grains, protein and fiber, is a good place to start. The WHO also notes that healthy eating and physical activity help, even when they don’t lead to weight loss.

Move most days

For adults, the guideline suggests 150 to 300 minutes of moderate activity a week, like brisk walking, or 75 to 150 minutes of vigorous activity, like running. It also suggests muscle-strengthening activity on two days a week that aren’t back to back. If that sounds like a lot, start smaller. Every bit of movement counts.

Care for your mood and sleep

Your mental health matters as much as your physical health. If you often feel low or anxious, tell a healthcare professional, because talking therapy and other support can help. Mention snoring or daytime sleepiness too, since sleep apnea is more common with PCOS.

Ask about medicines

Depending on your symptoms and goals, a healthcare professional may suggest:

• the combined birth control pill, to make periods more regular and help with extra hair and acne
• metformin, a medicine that helps your body use insulin
• medicines that block androgens, for extra hair or acne
• if you want to get pregnant, medicines that help you release an egg, or other fertility treatments

PCOS can make it harder to get pregnant, but it doesn’t have to stand in your way. A healthcare professional can talk you through the options.

A word about weight

If you’ve been told to “just lose weight”, you know how unhelpful that can feel. For people at a higher weight, losing some weight can ease symptoms. But healthy habits help even when the scale doesn’t move, and your health matters at every size.

When to get checked

It’s worth seeing a healthcare professional if:

• your periods are often more than 35 days apart, you have fewer than eight a year, or they’ve stopped
• extra hair, thinning hair or acne is bothering you
• you’re having trouble getting pregnant
• you notice dark, thick patches of skin
• you often feel low, anxious or tired

It helps to bring notes: the dates of your last few periods, the symptoms you’ve noticed and how often, and your questions. OvaReset’s health summary turns your daily check-ins into one page you can share if you want to.

The bottom line

PCOS, now also called PMOS, is common, real and manageable. It’s not your fault, and you don’t have to figure it out alone. Start with one small step, like a walk after dinner or writing down your cycle dates, and get support when you need it. Every day is a fresh start.